According to the rules of every tactical system I've seen, tokens next to each other have a distance of 1 grid unit between each other.
For auras, since the distance is from center of nearest grid unit encompassed by source token to similar center of grid unit on target token, then the aura effect should still apply. (i.e. If aura is 10 ft., then the target must be "within" 10 ft; not adjacent to 10 ft. That means that any token with 2 grid units (assuming 5 ft. per unit without diagonal multiplier) would be affected.) This is also assuming that auras radiate from the edge of the creature, rather than the center. (which is vague in most game systems)
I'm looking at the functions right now. And other than what appears to be some sort of rounding bug that I'm investigating on maps with non-integer grids, the calculations are correct.
Regards,
JPG
EDIT: And the rounding issue affects all distance calculations, not just the API version.

